A chemical peel is a skin-resurfacing procedure in which a chemical solution is applied to skin to peel away the top layers. The skin that grows back after a chemical peel is smoother and younger looking.

Chemical peels are used to treat wrinkles, skin discoloration and scars — typically on the face. A chemical peel can be done alone or in combination with other cosmetic procedures.

A chemical peel can be used to treat various skin problems. Depending on the issues you're addressing with the procedure, you'll choose a chemical peel in one of three depths:

Light chemical peel. A light, or superficial, chemical peel removes the outer layer of skin (epidermis). It can be used to treat fine wrinkles, acne, uneven skin tone and dryness. You might have a light chemical peel as often as once a week for up to six weeks — depending on your desired results.

Medium chemical peel. This type of chemical peel removes skin cells from the epidermis and from portions of the upper part of your middle layer of skin (dermis). A medium chemical peel can treat wrinkles, acne scars and uneven skin tone. You might repeat a medium chemical peel every six to 12 months to maintain results.

Deep chemical peel. A deep chemical peel removes skin cells from the epidermis and from portions of the mid to lower layer of your dermis. Your doctor might recommend a deep chemical peel if you have deeper wrinkles, scars or precancerous growths.

A chemical peel can't eliminate deep scars or reduce the size of pores.

A chemical peel can cause various side effects, including:

Redness. A chemical peel will cause treated skin to become red. After a medium or deep chemical peel, redness might last for several months.

Scarring. Rarely, a chemical peel can cause scarring — typically on the lower part of the face. Antibiotics and steroid medications can be used to soften the appearance of these scars.

Changes in skin color. A chemical peel can cause treated skin to become darker than normal (hyperpigmentation) or lighter than normal (hypopigmentation). Hyperpigmentation is more common after superficial peels, while hypopigmentation is more common after a deep peel. Changes in skin color are more common in people who have darker skin and can be permanent.

Acne. Tiny white bumps (milia) on the skin are possible after a chemical peel. Acne also commonly develops as treated skin heals — due to previous acne or the use of oily creams on newly formed skin.

Infection. A chemical peel can cause a flare-up of the herpes virus — the virus that causes cold sores. Rarely, a chemical peel can lead to a bacterial or fungal infection.

Heart, kidney or liver damage. A deep chemical peel uses carbolic acid (phenol), which can damage the heart muscle and cause the heart to beat irregularly. Phenol can also harm the kidneys and liver. To limit exposure to phenol, a deep chemical peel is done in portions at 10- to 20-minute intervals.

A chemical peel isn't for everyone. Your doctor might caution against a chemical peel or certain types of chemical peels if you:

Have taken the acne medication isotretinoin (Amnesteem, others) in the past six months

Have a dark complexion

Have red hair and a pale, freckled complexion

Have a personal history of ridged areas caused by an overgrowth of scar tissue (keloids)

Have abnormal skin pigmentation

Have facial warts

Are pregnant or breast-feeding

Before you have a chemical peel, your doctor will likely:

Review your medical history. Be prepared to answer questions about current and past medical conditions — especially any heart, kidney or liver conditions if you're considering a deep chemical peel. Tell your doctor about any medications you're taking or have taken recently — particularly those that might make your skin sensitive to the sun — as well as any cosmetic procedures you've had in the past. Be sure to tell your doctor if you've been using a retinoid cream (tretinoin), which can enhance the penetration of some chemical peels.

Do a physical exam. Your doctor will inspect your skin and the area to be treated. This will help him or her determine what type of chemical peel you might benefit from most and how your physical features — for example, the tone and thickness of your skin — might affect your results.

Discuss your expectations. Talk with your doctor about your motivations and expectations, as well as the potential risks. Make sure you understand how many treatments you might need, how long it'll take to heal and what your results might be.

If you decide to proceed with the chemical peel, you might also need to:

Take antiviral medication. If you have a history of herpes infections around your mouth, your doctor will likely prescribe an antiviral medication before and after treatment to help prevent a viral infection.

Use glycolic acid lotion. If you're having a light chemical peel using glycolic acid, your doctor might recommend using a glycolic acid lotion for two weeks before treatment to ensure a more uniform peel. Using the lotion ahead of time also helps you find out if you're sensitive to glycolic acid.

Use a retinoid cream. If you're having a light or medium chemical peel, your doctor might recommend using a retinoid cream (tretinoin) beforehand to shorten your treatment time and speed the healing process.

Use a bleaching agent. Your doctor might recommend using a bleaching agent (hydroquinone) and a retinoid cream (tretinoin) before or after the procedure to prevent skin darkening.

Avoid unprotected sun exposure. Too much sun up to two months before the procedure can cause permanent irregular pigmentation in treated areas. Discuss sun protection and acceptable sun exposure with your doctor.

Arrange for a ride home. If you'll be sedated during a medium or deep chemical peel, you'll need help getting home after the procedure.

A chemical peel is typically done in an office-based procedure room or outpatient surgical facility. Before the procedure, your doctor will clean your face and might cover your eyes with ointment, gauze, tape or goggles. He or she might also protect your hair.

Pain relief isn't typically needed for a light chemical peel.

If you're having a medium chemical peel, you might have the option of taking a sedative and a painkiller.

If you're having a deep chemical peel, your doctor will likely numb your skin with a local anesthetic and give you a sedative or use regional anesthesia — which numbs a certain part of your body.

During the procedure

During a light chemical peel:

Your doctor will use a brush, cotton ball, gauze or sponge to apply a chemical solution typically containing glycolic acid or salicylic acid. The treated skin will begin to whiten.

You might feel mild stinging while the chemical solution is on your skin — up to 10 minutes.

Your doctor will apply a neutralizing solution or wash treated skin to remove the chemical solution.

During a medium chemical peel:

Your doctor will use a cotton-tipped applicator or gauze to apply a chemical solution containing trichloroacetic acid, sometimes in combination with glycolic acid. The treated skin will begin to whiten.

After a few minutes, your doctor will apply cool compresses to soothe treated skin. You might also be given a hand-held fan to cool your skin. No neutralizing solution is needed, however.

You might feel stinging and burning for up to 20 minutes.

During a deep chemical peel:

You'll be given intravenous (IV) fluids and your heart rate will be closely monitored.

Your doctor will use a cotton-tipped applicator to apply carbolic acid (phenol) to your skin. Treated skin will begin to turn white or gray.

To limit your exposure to phenol, your doctor will do the procedure in portions at 10- to 20-minute intervals. A full-facial procedure might take 60 to 90 minutes.

After the procedure

After a chemical peel of any depth, follow your doctor's directions for cleansing, moisturizing and applying protective ointments to your skin.

After a light chemical peel, treated skin will be red, dry and mildly irritated — although these effects might be less noticeable with each repeat treatment. Your doctor might apply a protective ointment, such as petroleum jelly, to soothe the area. In some cases, a crust might form over treated skin as it begins to heal.

Treated areas develop new skin about three to seven days after a light chemical peel. New skin might temporarily be lighter or darker than normal.

After a medium chemical peel, treated skin will be red, tight and swollen. You'll feel stinging. Your doctor might apply a protective ointment, such as petroleum jelly, to soothe the area. Use ice packs for comfort and sleep in a semi-reclined position to reduce swelling.

You'll likely schedule a checkup 24 hours after treatment and another checkup two to three days after treatment so that your doctor can monitor healing.

As swelling decreases, treated skin will begin to form a crust and might darken or develop brown blotches. Treated areas develop new skin about five to seven days after a medium chemical peel, but redness might last for months.

After a deep chemical peel, you'll experience severe redness and swelling. You'll also feel burning and throbbing, and your eyelids might swell shut. Your doctor will apply a watertight dressing containing zinc oxide to treated skin. He or she might also prescribe painkillers. Sleep in a semi-reclined position to reduce swelling.

You'll likely schedule a checkup 24 or 48 hours after treatment so that your doctor can remove the dressing and clear away any yellowish liquid oozing from treated skin.

Treated areas will develop new skin within about two weeks after a deep chemical peel, although cysts or white spots might appear for several weeks and redness might last for months. Treated skin might become darker or lighter than normal or lose the ability to tan.

You might prefer to remain at home while you're healing from a chemical peel. Once new skin completely covers the treated area, you can use cosmetics to conceal any redness.

A light chemical peel can improve skin texture and tone, as well as decrease the appearance of fine wrinkles. The results will be subtle at first, but will increase with repeated treatments. After a light chemical peel, avoid sun exposure until new skin completely covers the treated area.

If you have a medium chemical peel, treated skin will be noticeably smoother after the procedure. Your doctor might recommend avoiding sun exposure for several months.

After a deep chemical peel, you'll see a dramatic improvement in the look and feel of treated areas. You'll need to protect your skin from the sun permanently to prevent changes in skin color.

Keep in mind that chemical peel results might not be permanent. As you age you'll continue to acquire lines by squinting and smiling. New sun damage can also reverse your results and cause changes in your skin color.

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